For 4.5 billion years, life evolved on planet Earth. Not once were the inhabitants of this tiny blue mote of dust able to gaze upon their home as one entity. To them it had always been an endless land without borders and an endless supply of food and resources. Most of them were blissfully unaware that they could ever venture further, and so they accepted the boundaries of their existence unquestionably. Once humans started making tools, we were taken down a path of discovery that would let us escape the bounds of our shrinking world. Finally, just over 70 years ago, we were able to escape the Earth and look back, seeing the planet as just one of many worlds.
Looking at the Earth from space has had two major milestones – seeing the Earth in a snapshot, and seeing it change over time. When studying a system, it’s valuable to observe the system over time to see how it changes and characterize it’s behaviour. Orbiting the Earth offers a snapshot of the planet because we can’t really look at one spot over time. Except for one interesting property of orbital mechanics.
The further you travel from the body you’re orbiting, the slower you orbit, meaning there is a point where you can go far enough from Earth to orbit at a speed equal to the planet’s rotation speed. This is geostationary orbit.
Aside from observing the day and night cycle, it’s fascinating to see the movements of cloud and wind patterns. Even on an hourly time scale the Earth is a living, changing system. If we could observe it on the scale of millions of years we would see the land masses come alive as well.
It’s wonderful that a view like this is accessible by so many people, that we can gain a deeper understanding of our place in the universe, and understand how inherently fragile it is. The change we observe is negative too, and we are having an impact whether we want to or not. The next step in our growth as a global species is to learn to control the effect we have on the planet, so that we don’t end up destroying the only place we can live.